Christianity and After, Petra
In the 4th century AD, with the spread of Christianity from Constantinople throughout the Byzantine Empire, Petra became the seat of a Bishopric and some of the former pagan buildings were converted into churches.
The Urn Tomb was converted into a church in 446 AD and Al-Deir (The Monastery) has crosses on its interior walls, which may be consecration marks. The city gradually contracted and buildings were divided up and used for different purposes. No Nabataean inscriptions date from after the late 4th century AD. Subsequently a series of strong earthquakes damaged the city and one in the mid 8th century AD may have dealt the deathblow.
Certainly when the Muslim Umayyad dynasty established its capital in Damascus in 661 AD, Petra found itself far from the center of power. The Crusaders built some fortifications in Petra in the 12th century AD on the top of the hill of Al-Habees as an outpost to their large castle at Shobak, 30 kilometers north of Petra. After once again becoming a stopping place for caravans in the 13th to 15th centuries AD, albeit without its former wealth and glory, the city lost its commercial importance.
In subsequent centuries, it was inhabited only by local Bedouins and their animals. The fabled Nabataeans capital was forgotten by Europeans until Burckhardt's arrival on the scene in 1812.
Since Burkhart's discovery early this century, many archaeological teams from Jordan and various other countries have carried out excavations in Petra. It is obvious however, even to the most casual observer that much more still remains to be discovered by future generations.